Federal and local authorities are investigating another suspicious item after a backpack was found containing up to five devices in New Jersey on Sunday.
The FBI Newark tweeted that it was "a suspicious package with multiple improvised explosive devices."

The backpack was found in a wastebasket in Elizabeth, New Jersey, outside a neighborhood pub and located about 500 feet from a train trestle, said the city’s mayor Chris Bollwage.
"Whoever threw it into the can was probably trying to get rid of it. It’s not in a highly congested area," Bollwage told CNN.
On Sunday around 9:30 p.m., two men found the backpack in the garbage can and alerted police when they saw wires and a pipe, he said. No cell phones or electronic timing devices were found on the devices, the mayor said.
There is no indication whether the latest incident in Elizabeth is connected to the bombing in a New York City neighborhood that injured 29 people and the explosion from a garbage can near a charity run in New Jersey. In the other New Jersey incident, investigators discovered three pipe-bomb-type devices wired together, but no one was wounded.

Bomb technicians from the FBI, the county and the New Jersey State Police arrived on scene in Elizabeth and a robot was sent to examine the devices.
"In the course of rendering one of the devices safe, it detonated. There are no injuries & law enforcement personnel are at the scene processing evidence," according to a tweet from FBI Newark account.
The device was detonated in a controlled setting, Bollwage said. The sound of the explosion reverberated loudly as heard on video filmed by local media.
"The robots that went in to disarm it, cut a wire and it exploded. I know there are other devices, I don’t know what they’re made up of but they’re going to have to be removed," Bollwage said.
The remaining four devices will be transferred in protective cases to a local site and then will be taken to the FBI laboratory at Quantico, Virginia, Bollwage said.
Police checked all garbage cans in the immediate area, but found no other suspicious items.

All trains going through Elizabeth station on both New Jersey Transit and Amtrak lines have been suspended, according to the respective transportation agencies. It was yet unclear when train service would re-open, but commuters were advised to seek alternate means of transportation. Elizabeth is located about 16 miles southwest of New York City.

New York incident

In New York, investigation over Saturday’s bombing continued as surveillance videos showed the same man near the site of the explosion and another location where a pressure-cooker device was found four blocks away, multiple local and federal law enforcement sources told CNN.
Saturday’s explosion shook New York City’s Chelsea neighborhood and sent panicked people scrambling for cover. By Sunday, 26 of the injured who had been admitted to hospitals had been released.
A few blocks away from the blast site and shortly after the explosion occurred, investigators found one possible lead: a pressure cooker, with dark-colored wiring sticking out, connected by silver duct tape to what appears to be a cellphone, officials said.
Shortly before 9 p.m. Sunday, the FBI and NYPD conducted a traffic stop of a vehicle of interest in the investigation, according to a statement from FBI. No one has been charged with any crime and the investigation is ongoing, the statement said.

3 attacks on US soil

The blast occurred on the same day an explosion went off near a Marine Corps charity run in New Jersey and a man stabbed nine people at a Minnesota mall. Authorities are investigating all three incidents as possible terror acts.

The Department of Homeland Security is actively monitoring and participating in the investigations in New York and New Jersey. Investigators found similarities between the explosives used in both states, according to multiple law enforcement officials, but authorities said they have not concluded the incidents are linked.
"We do not have any specific evidence of a connection, but that will continue to be considered," New York City Mayor Bill de Blasio said. "We’re not taking any options off the table."
In New York, law enforcement officials and the mayor said that without knowing who’s responsible or what the motive was, it’s too soon to call the Saturday bombing a terror attack.
"We know it was a very serious incident, but we have a lot more work to do to be able to say what kind of motivation was behind this," de Blasio told reporters Sunday. "Was it a political motivation? Was it a personal motivation? We do not know that yet."
Suspicious device found nearby
The blast occurred around 8:30 p.m. at 23rd Street between 6th and 7th Avenues. Investigators believe the blast was caused by an explosive device in or near a dumpster, a law enforcement source told CNN. Four blocks away on 27th Street, a pressure-cooker device was found with a piece of paper with writing on it close by, officials said.
Surveillance video shows a man dragging what appears to be a duffel bag with wheels near the site of the West 23rd street explosion about 40 minutes before the blast, according to multiple local and federal law enforcement sources.

About 10 minutes later, surveillance video shows the same man with what appears to be the same duffel bag on West 27th street, multiple law enforcement sources said.
In the video, the man leaves the duffel bag where police later found the unexploded pressure cooker. After he leaves, the video shows two men removing a white garbage bag believed to contain the pressure cooker from the duffel bag and leaving it on the sidewalk, according to a senior law enforcement official and another source familiar with the video.

Investigators have not determined if those two men are connected to the man with the duffel bag on both streets, the sources said.
The device was transported to the NYPD Bomb Squad facility at Rodman’s Neck Range in the Bronx.
NYPD and FBI Bomb technicians rendered the device safe. A forensic examination of the device and its components will be conducted at the FBI Laboratory at Quantico, Virginia.

’New York is up and running’

New Yorkers will see an increased police presence around the city, de Blasio said.

Stepped-up security across the city is common as world leaders arrive for the United Nations General Assembly meeting, which is underway.
"You should know you will see a very substantial NYPD presence this week — bigger than ever," de Blasio said.
New York Gov. Andrew Cuomo added that 1,000 additional New York State Police officers and National Guard troops will be deployed to patrol bus terminals, airports and subway stations.
The increased policing, Cuomo said, is "just to err on the side of caution."
"I want New Yorkers to be confident when they go back to work on Monday that New York is up and running and we’re doing everything that we need to do," he said.